Magnetic recording media for video or audio devices or computers are required to have excellent wear resistance since they are vigorously rubbed against a magnetic head for reproduction of recorded signals. This causes wear of the magnetic coating layer. It is also required to impart electric conductivity to the magnetic layer in order to prevent adhesion of dust in air due to static charge.
These requirements have hitherto been fulfilled by incorporating non-magnetic powders that are harder than magnetic powders, such as chromic oxide powders (Cr.sub.2 O.sub.3) and aluminum oxide powders (Al.sub.2 O.sub.3), and carbon black to the magnetic coating layer as disclosed in, e.g., Japanese Patent Publication Nos. 39402/74, 18561/77, U.S. Pat. No. 3,833,412, etc.
With the recent remarkable improvement in recording density and S/N ratio, magnetic substances used in the magnetic recording medium have been made finer. Under such circumstances, the above-described combination of chromic oxide powders, aluminum oxide powders, etc. and carbon black cannot sufficiently cope with the development of high-density recording or high S/N ratio, even though they are effective on wear resistance and abrasion of a magnetic head.